Male C. pallida are able detect the pheromones which females release and use them to locate female burrows. When a virgin female is about to emerge from her burrow, she releases a scent that wafts up through the soil and is detected by the antenna of the males. This has led to males developing a very acute olfactory sense. Freshly-killed females have been buried to test whether sound also plays a part in male signaling. In these tests, male bees still dug up the dead females, proving that pheromone signaling is the only pathway. Males have also been observed to dig up other males. This shows that males and virgin females give off similar pheromones. Oddly, males also sometimes dig up other digger bee species. It is currently unknown why this occurs.[6]